1. Field of the Invention
This invention relates to printed circuit card assemblies of the type having an edge connector arranged for insertion into a corresponding connector of a backplane, and more particularly to a device for retaining the printed circuit card in place.
2. Description of the Prior Art
In the present state of the art, it is the usual practice in large electronic systems to arrange printed circuit boards or cards each in a vertical plane with the edge connectors at one end. The corresponding connector jacks are then arranged on end, with the top and bottom ends fastened to two horizontal bars. The printed circuit board is supported along its top and bottom edges by some sort of plane usually with restraining guides.
Generally, unless the equipment is designed for military or mobile use no provision is made to lock the cards in their respective positions since the force of each of the large number of terminals of the connector is more than adequate to hold them in place. But, when the equipment is located at a site where there is some degree of vibration, there may be a slight amount of creep, whereby the card may come out of its connector in time. This is not normally a problem on full size cards since the maintenance personnel can readily detect and correct this before electrical contact is lost. However, when short cards are jacked into connectors of a backplane where they are not visible to the maintenance personnel without the removal of other cards it becomes a major problem.